1. Field of the Invention
This invention relates to improvements in a modified Gauss type photographic lens.
2. Description of the Prior Art
The Gauss type lens and its modifications have heretofore been widely used and their performances have been considerably improved. However, in order that such lens may be used with a single lens reflex camera, the back focal distance thereof must be increased and this greatly affects the correction of the various aberrations and accordingly aggravates the performance. To make such lens, therefore, use must be made of glass materials having various refractive indices and Abbe numbers, which means higher cost of the manufacture, and this could never be said to be sufficiently satisfactory.